The biggest issues with Appimages is that it doesn't have a built in update mechanism, also discoverablity is non existant (as @Guldoman says).

These are my points for Flatpak:

All relevent Linux distrobutions support it; openSuse, Arch, Manjaro, Ubuntu, Debian, Fedora, ...
Dependency versions are better defined
Discoverablity: Most distributions that using flatpaks include flathub as a source, this means that in the app store listings from flathub are included as well. (e.g.: open app store, search 'editor lua', top listing 'lite-xl')
Updates happen with the app store (open app store, click update, updates flatpak and [apt, rpm, aur, ..]
Linux has come to a point that there are users that do not want to install programs from a tar.gz file, using the app store provided already does enough.

Flatpak support #441

Description